CN113727380B

CN113727380B - Disaster recovery method and device

Info

Publication number: CN113727380B
Application number: CN202110924647.3A
Authority: CN
Inventors: 李沸乐; 杨文聪
Original assignee: China United Network Communications Group Co Ltd
Current assignee: China United Network Communications Group Co Ltd
Priority date: 2021-08-12
Filing date: 2021-08-12
Publication date: 2023-06-16
Anticipated expiration: 2041-08-12
Also published as: CN113727380A

Abstract

The application discloses a disaster recovery method and device, and relates to the field of communication. The method comprises the step that when the connection between the edge user plane functional network element and the core network is disconnected, the edge user plane functional network element keeps the user plane connection of the terminal equipment in the local area network, and further, data are transferred in the local area network according to the user plane connection of the terminal equipment in the local area network. By the method, after the core network is disconnected with the local area network, the internal service of the local area network can continue to operate.

Description

Disaster recovery method and device

Technical Field

The present disclosure relates to the field of communications, and in particular, to a disaster recovery method and apparatus.

Background

The user plane function (user plane function, UPF) network element of the fifth generation mobile communication technology core network (5th generation mobile communication technology core,5GC) can be divided into an internet (abbreviated as public network) UPF network element and an edge UPF network element according to deployment positions and applications. Typically, the public network UPF network elements are deployed in a Data Center (DC), such as a large-area machine room. The public network UPF network element is used for providing data forwarding service for the user equipment accessing the public network. The edge UPF network element may be deployed in an edge scenario such as a district, city, county, park, etc. The edge UPF network element is configured to provide a data forwarding service for a user equipment in a private local area network (abbreviated as private network) to access the public network nearby. A private network that deploys edge UPF network elements under a private network architecture may be referred to as a hybrid private network. The requirements of users in private networks on data security, network reliability and the like are higher than those of users in public networks.

In the field of computer communications, disasters are defined as: due to artificial or natural reasons, the communication system is seriously failed or paralyzed, so that the service functions supported by the communication system are stopped or the service level is not acceptable, and the state exceeds a certain time of emergency. When a disaster occurs, the connection between the private network and the public network is disconnected, and the public network UPF network element and the edge UPF network element release the protocol data unit (protocol data unit, PDU) session of the user equipment, so that the connection between the user equipment and the private network in the garden area is interrupted and the service application is terminated, and the reliability and the stability of the transmission of the garden service cannot be ensured. However, at present, there is no disaster recovery method designed for the hybrid private network networking architecture, and how to design a disaster recovery method according to the hybrid private network networking architecture is a problem to be solved.

Disclosure of Invention

The application provides a disaster recovery method and device, which solve the problem of how to maintain reliable and stable transmission of private network business when public network and private network are not connected under a hybrid private network structure.

In a first aspect, a disaster recovery method is provided, where the method is performed by an edge user plane function network element, and includes: if the connection between the edge user plane function network element and the core network is disconnected, the edge user plane function network element keeps the user plane connection of the terminal equipment in the local area network; and the edge user plane function network element transfers data in the local area network according to the user plane connection of the terminal equipment. When the core network is disconnected from the local area network, the edge user plane function network element in the private network keeps continuously keeping the user plane connection of the terminal equipment, so that the service data can be continuously forwarded between the terminal equipment and the local area network data network. After the core network is disconnected with the local area network, the service inside the private network can continue to run.

In one possible design, the edge user plane function network element maintaining the user plane connection of the terminal device in the local area network includes not releasing the PDU session of the terminal device in the local area network. The edge user plane function network element does not release PDU session of the terminal equipment in the local area network, so that the service data of the terminal equipment can still be continuously forwarded between the terminal equipment and the local area network data network under the condition that the core network is disconnected with the local area network, and the problem of service interruption in the range of the local area network caused by the connection interruption of the core network and the local area network is avoided.

In one possible design, if the edge user plane function network element is restored to the core network connection, the edge user plane function network element obtains a first type PDU session of the terminal device in the local area network. The first PDU session comprises PDU session of terminal equipment in local area network maintained by the edge user plane function network element between disconnection and connection recovery of the edge user plane function network element and the core network; furthermore, the edge user plane function network element acquires a second type PDU session sent by a first network element in the core network, judges whether the first type PDU session and the second type PDU session have the same PDU session, and if the same PDU session exists, the edge user plane function network element keeps the same PDU session. If different PDU sessions exist, the edge user plane function releases the different PDU sessions, so that tunnel resources occupied by the different PDU sessions are released, and the utilization rate of the tunnel resources is improved.

In one possible design, the edge user plane function network element sends a first type PDU session to a first network element in the core network.

In a second aspect, a disaster recovery method is provided, where the method is performed by a first network element, and includes: when the first network element is disconnected from the first local area network, the first network element judges whether the keep-alive information contains the identification of the first local area network. The keep-alive information is used for indicating a local area network to be kept in communication connection; if the keep-alive information comprises the identifier of the first local area network, the connection state of the terminal equipment and the first network element in the first local area network is maintained; and if the keep-alive information does not contain the identification of the first local area network, releasing the connection state of the terminal equipment and the first network element in the first local area network. Thus, after the connection between the core network and the first local area network is disconnected, the first network element in the core network judges whether the first local area network is the local area network needing to keep communication connection according to the keep-alive information, and if so, the connection state of the terminal equipment in the first local area network and the first network element is kept. When the core network and the local area network are restored to be connected, the terminal equipment in the first local area network does not need to initiate a registration process again, so that service interruption in the first local area network is avoided, and the stability of service transmission in the first local area network is ensured.

In one possible design, the first network element includes an access mobility management function (access and mobility management function, AMF) network element and a session management function (session management function, SMF) network element.

In one possible design, if the first network element is an AMF network element, the first network element is connected to a radio access network element in the first local area network through an N2 interface, and the first network element keeps the terminal device in the first local area network connected to the control plane of the first network element; if the first network element is an SMF network element, the first network element is connected with an edge user plane function network element in the first local area network through an N4 interface, and the first network element keeps PDU session between terminal equipment in the first local area network and the first network element.

In one possible design, the keep-alive information is configured before the first network element disconnects from the first local area network. By pre-configuring the keep-alive information on the first network element, the first network element can store the connection state of the terminal equipment in the first local area network and the first network element when the core network and the first local area network are suddenly out of connection, so that a registration process is not required to be restarted when the core network and the first local area network are restored to be connected, and further the stability of service transmission in the first local area network is ensured.

In one possible design, when the connection between the first network element and the first local area network is restored, the first network element acquires a second type PDU session between the terminal device in the first local area network and the first network element, wherein the second type PDU session comprises a PDU session between the disconnection of the first network element and the first local area network and the restoration of the connection, and the first network element maintains the PDU session of the terminal device in the first local area network; further, the first network element acquires a first PDU session sent by an edge user plane function network element in the first local area network; judging whether the same PDU session exists in the first-type PDU session and the second-type PDU session; if the same PDU session exists, the same PDU session is maintained. If different PDU sessions exist, the different PDU sessions are released, so that tunnel resources occupied by the different PDU sessions are reduced, and the utilization rate of the tunnel resources is improved.

In one possible design, the first network element sends a second type PDU session to an edge user plane function network element in the first local area network.

In a third aspect, there is provided a communication apparatus comprising: the processing unit is used for keeping the user plane connection of the terminal equipment in the local area network when the edge user plane functional network element is disconnected with the core network; and is also used for forwarding data in the local area network according to the user plane connection of the terminal equipment.

In a possible design, the processing unit is specifically configured to not release the protocol data unit PDU session of the terminal device in the local area network.

In one possible design, the device further comprises a receiving unit. And the receiving unit is used for acquiring the first PDU session of the terminal equipment in the local area network when the connection between the edge user plane functional network element and the core network is restored.

In one possible design, the first type of PDU session includes a PDU session of a terminal device in a local area network maintained by an edge user plane function network element between disconnection and connection recovery of the edge user plane function network element and a core network; and the receiving unit is also used for acquiring the second-class PDU session sent by the first network element in the core network. And the processing unit is also used for judging whether the first-type PDU session and the second-type PDU session have the same PDU session. The processing unit is specifically configured to maintain the same PDU session when the first type PDU session and the second type PDU session exist in the same PDU session.

In one possible design, the system further comprises a transmitting unit. And the sending unit is used for sending the first-type PDU session to the first network element in the core network.

In a fourth aspect, there is provided a communication apparatus comprising: the processing unit is used for judging whether the keep-alive information contains the identification of the first local area network when the first network element is disconnected from the first local area network; the processing unit is further used for maintaining the connection state of the terminal equipment and the first network element in the first local area network when the keep-alive information comprises the identifier of the first local area network; and the processing unit is further used for releasing the connection state of the terminal equipment and the first network element in the first local area network when the keep-alive information does not contain the identification of the first local area network.

In a possible design, the processing unit is specifically configured to not delete the protocol data unit PDU session between the terminal device and the first network element in the first local area network.

In one possible design, the first network element comprises an access mobility management function AMF network element and a session management function SMF network element.

In one possible design, the processing unit is specifically configured to, when the first network element is an AMF network element, connect the first network element with a radio access network element in the first local area network through the N2 interface, and keep the terminal device in the first local area network connected with the control plane of the first network element. The processing unit is specifically configured to, when the first network element is an SMF network element, connect the first network element with a radio access network element in the first local area network through an N2 interface, and keep a PDU session between the terminal device in the first local area network and the first network element.

In one possible design, the keep-alive information is configured before the first network element disconnects from the first local area network.

In one possible design, the device further comprises a receiving unit, when the connection between the first network element and the first local area network is restored, a second type PDU session between the terminal device in the first local area network and the first network element is obtained, wherein the second type PDU session comprises the PDU session between the disconnection between the first network element and the first local area network and the connection restoration, and the PDU session between the terminal device in the first local area network maintained by the first network element; the receiving unit is also used for acquiring a first PDU session sent by an edge user plane function network element in the first local area network; the processing unit is further used for judging whether the same PDU session exists in the first-type PDU session and the second-type PDU session; the processing unit is specifically configured to maintain the same PDU session when the same PDU session exists in the first type PDU session and the second type PDU session.

In a possible design, the method further includes a sending unit, configured to send the second type PDU session to an edge user plane function network element in the first local area network.

In a fifth aspect, there is provided a communication apparatus comprising: a processor and a memory; the memory is configured to store computer-executable instructions that the processor executes to cause the communication device to perform any one of the methods provided in the first or second aspects above.

In a sixth aspect, there is provided a computer readable storage medium storing computer instructions that, when run on a computer, cause the computer to perform any one of the methods provided in the first or second aspects.

In a seventh aspect, there is provided a computer program product comprising computer instructions which, when run on a computer, cause the computer to perform any one of the methods provided in the first or second aspects.

In an eighth aspect, there is provided a chip comprising: processing circuitry and transceiver pins for implementing any of the methods provided in the first or second aspects above. The processing circuit is used for executing processing actions in the corresponding method, and the receiving and transmitting pins are used for executing receiving/transmitting actions in the corresponding method.

The technical effects caused by any one of the foregoing third to eighth possible designs may be related to the technical effects caused by the corresponding designs in the first or second aspect, and are not described herein.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate and do not limit the invention.

Fig. 1 is a schematic diagram of a hybrid private network structure provided in an embodiment of the present application;

FIG. 2 is a schematic flow chart of a disaster recovery method according to an embodiment of the present application;

FIG. 3 is a schematic flow chart of another disaster recovery method according to an embodiment of the present application;

FIG. 4 is a schematic flow chart of another disaster recovery method according to an embodiment of the present application;

FIG. 5 is a schematic flow chart of another disaster recovery method according to an embodiment of the present application;

FIG. 6 is a schematic flow chart of another disaster recovery method according to an embodiment of the present application;

FIG. 7 is a schematic flow chart of another disaster recovery method according to an embodiment of the present application;

fig. 8 is a schematic diagram of a communication device according to an embodiment of the present application;

fig. 9 is a schematic diagram of a communication device according to an embodiment of the present application;

Fig. 10 is a schematic hardware structure of a communication device according to an embodiment of the present application.

Detailed Description

The following description of the technical solutions in the embodiments of the present application will be made clearly and completely with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.

Along with the global digital wave and tide roll, the enterprise market is undoubtedly a key point for the growth of 5G network construction, and operators and equipment manufacturers at home and abroad are highly concerned about the research and landing of an enterprise market private local area network (hereinafter referred to as private network). For vertical industries (such as hospitals, automobile factories, etc.) that require private network service data to be processed without camping and with low delay to handle local services, while hopefully reducing the costs of core network construction and daily operation and maintenance, operators typically construct hybrid private networks for the vertical industries. The hybrid private network differs from the normal private network in that the hybrid private network is a dedicated edge UPF that deploys exclusive resources locally on a vertical industrial park, which shares a public network 5G core (5G core,5 gc) control plane with the public network and other parks. The special edge UPF provides network services such as user plane data message forwarding and the like for the vertical industry park. By locally deploying the special edge UPF with exclusive resources in the vertical industry park, private network internal services can be processed through the edge UPF without being sent to the public network UPF for processing, so that the processing time of the private network internal services is reduced, and the processing speed of the private network internal services is improved.

Referring to fig. 1, a schematic diagram of a hybrid private network structure is provided for an embodiment of the present application, where a hybrid private network 10 includes a private network 100 and a public network 110, and the private network 100 includes a terminal device 101, a radio access network (NG-RAN) network element 102, an edge UPF network element 103, and a Data Network (DN) 104.

The public network 110 includes an access mobility management function (access and mobility management function, AMF) network element 111, a session management function (session management function, SMF) network element 112, a UPF network element 113, and a unified data management (Unified Data Management, UDM) network element 114, etc. Fig. 1 is only a schematic diagram, and the hybrid private network may further include other network elements, where the number of network elements included in the hybrid private network is not limited in this embodiment of the present application.

The terminal device 101 may be a device having a wireless transceiving function. The terminal device 101 may have different names such as User Equipment (UE), an access terminal, a terminal unit, a terminal station, a mobile station, a remote terminal, a mobile device, a wireless communication device, a terminal agent, or a terminal apparatus, etc. Terminals may be deployed on land, including indoors or outdoors, hand-held or vehicle-mounted; may also be deployed on the surface of water (e.g., a ship, etc.); but may also be deployed in the air (e.g., on aircraft, balloon, satellite, etc.). The terminal devices may be cellular telephones, cordless telephones, session initiation protocol (session initi ation protocol, SIP) telephones, wireless local loop (wireless local loop, WLL) stations, personal digital assistants (personal digital assistant, PDA), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to wireless modems, vehicle-mounted or wearable devices, unmanned aerial vehicles (unmanned aerial vehicle, UAV) and Unmanned Aerial Vehicle Controllers (UAVC), virtual Reality (VR) terminal devices, augmented reality (augmented realit y, AR) terminal devices, wireless terminals in industrial control (industrial control), wireless terminals in self driving (self driving), wireless terminals in telemedicine (remote media), wireless terminals in smart grid (smart grid), wireless terminals in transportation security (transportation safety), wireless terminals in smart city (smart city), wireless terminals in smart home (smart home), etc. The terminal device may be mobile or stationary. The embodiment of the application does not limit the specific technology and the specific equipment form adopted by the terminal equipment. The terminal device 101 accesses the radio access network element 102 by wired or wireless means.

The radio access network element 102 may be a public private network shared base station within the park, and external visitor user terminals subscribing to the public network data network names (data network name, DNN), different types of user terminals subscribing to the public network DNN and the private network DNN may all normally access the network from the park shared base station and establish a protocol data unit (protocol data unit, PDU) session to the network subscribing to the corresponding DNN.

The radio access network element 102 is connected to the AMF network element 111 in the public network 110 through an N2 interface, and is connected to the edge UPF network element 103 through an N3 interface.

The edge UPF network element 103 is configured to provide a user plane data packet forwarding service for the private network 100, where the edge UPF network element 103 is connected to the radio access network element 102 through an N3 interface, connected to the SMF network element 112 in the public network 110 through an N4 interface, connected to the UPF network element 113 in the public network 110 through an N9 interface, and connected to the DN104 through an N6 interface. In this embodiment of the present application, the external public network visitor accessing the private network 100 through a wired or wireless manner may access the public network by adopting an uplink classifier (uplink classifier, ULCL), that is, the edge UPF network element 103 is used as a ULCL UPF, anchored to the public network UPF113, and for the data traffic belonging to the local service of the private network 100 on the terminal device 101, the data traffic is sent to the DN104 through the N6 interface, and for the internet service belonging to the public network 110 on the terminal device 101, the data traffic is sent to the public network UPF network element 113 through the N9 interface.

DN104 may also be a local data network (local area data network, LADN), which may be referred to as an intranet, where terminal device 101 may access the intranet through a PDU session in the campus, and where terminal device 101 leaves the service area of the intranet to release the PDU session.

DN104 is connected to edge UPF network element 103 through an N6 interface.

The AMF network element 111 is configured to manage registration, connection, access authentication authorization, mobility, and reachability management of the terminal device 101, and is connected to the radio access network element 102 in the private network 100 through the N2 interface.

The SMF network element 112 is configured to interact with the separate data plane, manage session establishment, update and release, and maintain protocol data unit (protocol data unit, PDU) session state, and is responsible for allocation management of the inter-network interconnection protocol (internet protocol, IP) of the terminal device 101. The SMF network element 112 is connected to the UPF network element 113 and the edge UPF network element 103 through an N4 interface.

The UPF network element 113 is configured to provide a data forwarding service for the terminal device 101 accessing the public network 110, where the UPF network element 113 is connected to the SMF network element 112 through an N4 interface, and is responsible for completing the processing of network user planes such as encapsulation and decapsulation of a GTP-U protocol on the user plane, packet routing and forwarding, packet inspection, qoS flow mapping, and the like by responding to a request of the SMF network element 112. The upstream and downstream user data streams are transferred to the edge UPF network element 103 via the N9 interface, and connected to the Internet (Internet) via the N6 interface.

The UDM network element 114 is used for storing and managing data and configuration files of the user.

The devices such as the wireless access network element and the edge user plane function network element in the private network 100 system are connected and communicated with the devices in the public network 110 system through a transmission network consisting of an access ring, a convergence ring and the like.

In the prior art, when the transmission network breaks down due to the construction damage or sudden disasters such as equipment failure of the transmission network, and the like, and interfaces such as N2, N4, N9 and the like between the private network and the public network simultaneously break down, and the public network and the private network are disconnected, the following main network element processing measures in the public network and the private network and the influence on users and services are adopted:

(1) Public network AMF network element: after the AMF network element detects the failure of the N2 interface with the private network base station, the N2 interface resource is released, all the connected state users associated with the N2 interface are converted into an idle state, meanwhile, the SMF network element informs the edge UPF network element to release N3 tunnels of the idle state users, the AMF network element cannot receive the signaling of periodic tracking area update (tracking area update, TAU) of the private network idle state users, and the resources occupied by the private network idle state users are released after a period of time (usually 54 minutes).

(2) Public network SMF network element: after the SMF network element detects the failure of the N4 interface connected with the edge UPF network element, the user activated on the edge UPF network element is deactivated, and the PDU session of the terminal equipment associated with the N4 interface is released.

(3) Private network edge UPF network element: after the edge UPF network element detects the N4 interface fault connected with the public network SMF network element, the user served by the SMF network element can be deactivated, the data packet related to the PDU session held by the SMF network element is discarded, and all tunnel resources and contexts related to the N4 interface are released.

Obviously, after the public network and the private network are out of connection in the current standard, the connection state and the PDU session of the UE in the private network are released on the GC control surface of the public network 5, and the PDU session of the terminal equipment in the private network is released by the UPF network element at the edge of the private network, so that the user connection in the area of the private network garden is interrupted and the service is terminated. And after the fault is recovered, the processing measures of the main network elements in the public network and the private network and the influence on the users needing to operate the service are as follows:

(1) Public network AMF network element: after the N2 interface is restored, the UE in the private network is connected with the AMF network element, and since the AMF network element has converted all the connected users associated with the N2 interface into an idle state, the UE in the private network needs to initiate registration again.

(2) Public network SMF network element and private network edge UPF network element: after the N4 interface is restored, the service transmission is interrupted because the SMF network element and the edge UPF network element have released the PDU session associated with the N4 interface. The UE in the private network needs to re-establish the PDU session to resume the service.

As can be seen from the above, since the connection state of the UE in the private network and the PDU session are released on the GC control plane of the public network 5, the PDU session needs to be re-registered and established by the UE in the private network, which again causes a temporary interruption and reconnection of the session, thereby causing a re-interruption of the service transmission in the private network. Therefore, the public network AMF network element, the SMF network element and the private network edge UPF network element defined by the existing third generation partnership project (3rd generation partnership project,3GPP) standard cannot support the disaster tolerance requirement under the mixed private network structure.

The embodiment of the application provides a disaster recovery method aiming at the requirement that private network service can be reliably and stably transmitted when the public network and the private network are not connected under the hybrid private network structure. By configuring keep-alive private network lists on the public network AMF network element and the SMF network element in advance and starting keep-alive functions of the AMF network element, the SMF network element and the edge UPF network element. When the N2, N4 and N9 interfaces between the public network and the private network are disconnected, the AMF network element of the public network checks the context of the connected UE associated with the broken N2 interface, and checks whether the connected UE associated with the N2 interface has established a PDU session with the private network DNN on the list of the keep-alive private network. If yes, the AMF network element performs service keep-alive. The public network SMF network element checks the context of the connected UE associated with the broken N4 interface, and checks whether the connected UE associated with the N4 interface has established PDU session with the private network DNN on the list of the keep-alive private network, if so, the SMF network element performs service keep-alive. And the edge UPF network element in the private network continuously keeps the user plane connection of the connected UE in the private network, so that the service data is ensured to be continuously forwarded between the UE and the private network, namely keep-alive operation. According to the disaster recovery method provided by the embodiment of the application, under the condition that no additional equipment or node modules are added, the key network element functions in the 5GC are enhanced, so that the requirement of service persistence stability transmission of a private network with high-reliability disaster recovery requirement can be accurately met when a public private network is out of connection under the mixed private network structure, and the service reliability of the private network is improved under the condition that the resource cost is not increased.

The following describes a disaster recovery method and device provided in the embodiments of the present application in detail with reference to the accompanying drawings.

As shown in fig. 2, an embodiment of the present application provides a disaster recovery method, which is performed by an edge user plane function network element, and when the edge user plane function network element is disconnected from a core network, the method includes the following steps.

S201, the edge user plane function network element keeps the user plane connection of the terminal equipment in the local area network.

In the embodiment of the present application, the core network may be a 5G core network, which may be referred to as a public network. The local area network may be a private local area network, which may be referred to as a private network.

The edge user plane function network element is connected with the SMF network element in the core network through an N4 interface and is connected with the UPF network element in the core network through an N9 interface. And when the N4 interface of the edge user plane function network element and the SMF network element in the core network is connected and the N9 interface of the edge user plane function network element and the UPF network element in the core network is failed, the connection between the edge user plane function network element and the core network is disconnected. When the connection between the edge user plane function network element and the core network is disconnected, the edge user plane function network element releases the user plane connection of the terminal equipment associated with the N4 interface and the N9 interface, so that the terminal cannot transfer network data in the local area network, and the service in the local area network is interrupted.

In the embodiment of the application, by starting the keep-alive function of the edge user plane function network element, when the connection between the edge user plane function network element and the core network is disconnected, the edge user plane function network element keeps the user plane connection of the terminal equipment in the local area network.

Specifically, the edge user plane function network element may not release the PDU session of the terminal device in the local area network.

S202, the edge user plane function network element transfers data in the local area network according to the user plane connection of the terminal equipment.

When the connection between the edge user plane function network element and the core network is disconnected, the edge user plane function network element can keep the user plane connection of the terminal equipment in the local area network, and the PDU session of the terminal equipment is not released, so that the terminal equipment can continue to transfer service data in the local area network, and the service in the local area network is not interrupted.

Based on the embodiment of fig. 2, by starting the keep-alive function of the edge user plane function network element, when the public network and the private network are disconnected, the edge user plane function network element continues to keep the user plane connection of the terminal equipment in the private network without releasing the PDU session of the terminal equipment, thereby ensuring that the terminal equipment can continue forwarding service data in the private network. Therefore, the service in the private network is not interrupted due to disconnection of the public network and the private network, and the continuity and stability of service transmission in the private network are ensured without adding extra resource cost.

As shown in fig. 3, when the edge user plane function network element is restored to the core network connection, the method further comprises the following steps.

S301, an edge user plane function network element acquires a first PDU session of terminal equipment in a local area network.

The first PDU session includes PDU session of terminal equipment in the LAN maintained by the edge user plane function network element between disconnection and restoration of connection between the edge user plane function network element and the core network.

It can be appreciated that, after the lan is disconnected from the core network, the terminal device in the lan cannot initiate connection to the SMF network element in the core network through the base station, that is, the terminal device in the lan cannot establish a new PDU session. The PDU session held by the edge user plane function network element in the lan may be released due to the selection of the user in the lan, so that the PDU session held by the edge user plane function network element may be different before the lan is disconnected from the core network and recovered from the connection.

Illustratively, the edge user plane function network element maintains the first PDU session, the second PDU session, and the third PDU session until the local area network is disconnected from the core network. When the local area network is disconnected with the core network, the user in the local area network releases the first PDU session, and the edge user plane function network element keeps the second PDU session and the third PDU session between the disconnection of the local area network and the core network and the connection recovery. I.e. the first type PDU session comprises a second PDU session and a third PDU session.

S302, the edge user plane function network element acquires a second-class PDU session sent by a first network element in the core network.

After the connection between the core network and the local area network is restored, the edge user plane function network element can acquire the second-class PDU session sent by the first network element in the core network through the N4 interface.

S303, the edge user plane function network element judges whether the first-type PDU session and the second-type PDU session have the same PDU session.

As a possible implementation, the edge user plane function network element traverses the first type PDU session and the second type PDU session with the PDU session as an index. If the first type PDU session and the second type PDU session exist for the same PDU session, then the following step 304 may be performed. If there are different PDU sessions for the first type PDU session and the second type PDU session, then the following step 305 may be performed.

S304, the edge user plane function network element keeps the same PDU conversation.

For example, if the first type of PDU session includes a second PDU session and a third PDU session, the second type of PDU session includes a first PDU session and a second PDU session, the edge user plane function network element maintains the same PDU session, i.e., the edge user plane function network element maintains the second PDU session.

S305, the edge user plane function network element releases different PDU sessions.

For example, if the first type of PDU session includes a second PDU session and a third PDU session, the second type of PDU session includes the first PDU session and the second PDU session, the edge user plane function network element releases the different PDU session, that is, the edge user plane function network element releases the third PDU session.

Based on the embodiment of fig. 3, by acquiring the first type PDU session maintained by the edge user plane function network element between disconnection and connection recovery of the core network and the local area network, comparing the first type PDU session with the second type PDU session sent by the first network element of the core network, maintaining the same PDU session in the two types of PDU sessions, ensuring the terminal equipment corresponding to the same PDU session, and after the connection of the local area network and the core network is recovered, the original session can be used without re-establishing a new PDU session, thereby avoiding the connection interruption of the terminal equipment and the first network element in the core network. And releasing different PDU sessions in the two PDU sessions, namely releasing tunnel resources occupied by the different PDU sessions, thereby improving the utilization rate of network resources.

After the connection between the core network and the local area network is restored, the edge user plane functional network element sends the first-type PDU session to the first network element in the core network through the N4 interface, so that the first network element in the core network can conveniently compare the first-type PDU session with the second-type PDU session, further, tunnel resources occupied by different PDU sessions are released, and the utilization rate of network resources is improved. Illustratively, as shown in FIG. 4, the method further comprises: s306, the edge user plane function network element sends the first PDU session to the first network element in the core network. Thus, the first network element in the core network receives the first-type PDU session.

As shown in fig. 5, an embodiment of the present application provides a disaster recovery method, which is performed by a first network element, and when the first network element is disconnected from a first lan, the method includes the following steps.

S501, the first network element judges whether the keep-alive information contains the identification of the first local area network.

In the embodiment of the present application, the plurality of local area networks and the core network share the GC control plane of the core network 5, and the first local area network refers to one of the plurality of local area networks.

The first network element is connected with a wireless access network element in the first local area network through an N2 interface, is connected with an edge user plane function network element in the first local area network through an N4 interface, and is also connected with the edge user plane function network element in the first local area network through an N9 interface. And when the N2 interface between the first network element and the wireless access network element in the first local area network and the N4 and N9 interfaces between the first network element and the edge user plane function network element in the first local area network are in faults, the first network element is disconnected with the first local area network. When the connection between the first network element and the first local area network is disconnected, the first network element releases the PDU session of the terminal equipment in the first local area network associated with the N2 and N4 interfaces, so that when the connection between the first network element and the first local area network is restored, the terminal equipment in the first local area network needs to reinitiate registration and reestablish the PDU session, thereby causing interruption of service data transmission in the first local area network.

In the embodiment of the present application, by starting the keep-alive function of the first network element, when the connection between the first network element and the first lan is disconnected, the first network element determines whether the keep-alive information includes the identifier of the first lan, where the keep-alive information is used to indicate the lan to be kept in communication connection, and may also be referred to as a keep-alive private network list. It should be noted that, the keep-alive information is configured to the first network element in advance before the first network element is disconnected from the first lan.

If the keep-alive information includes the identifier of the first lan, executing S502; if the keep-alive information does not contain the identity of the first local area network, S503 is executed.

S502, the first network element keeps the connection state of the terminal equipment and the first network element in the first local area network.

For example, see table 1 for a list of local area networks to be maintained in communication connection.

TABLE 1

LAN data network name
	ABCD.COM
FGHJ.COM
	ZXCV.COM

If the identifier of the first local area network is abcd.com, look-up table 1, and find the identifier of the first local area network in table 1, the first network element maintains the connection state between the terminal device in the first local area network and the first network element. Specifically, the first network element does not delete the PDU session between the terminal device and the first network element in the first local area network. In this way, when the first network element is connected to the first lan, the terminal device in the first lan does not need to reestablish the PDU session.

The first network element may be an AMF network element, which is connected to a wireless network element in the local area network through an N2 interface. The first network element may also be an SMF network element, where the SMF network element is connected to an edge user plane function network element in the local area network through an N4 interface.

If the first network element is an AMF network element, the first network element keeps the connection between the terminal equipment in the first local area network and the control surface of the first network element, and if the first network element is an SMF network element, the first network element keeps the connection between the terminal equipment in the first local area network and the control surface of the first network element.

S503, the first network element releases the connection state between the terminal equipment and the first network element in the first local area network.

For example, if the identifier of the first local area network is hjkl.com, and the table 1 is searched, and the identifier of the first local area network is not found in the table 1, the first network element releases the connection state between the terminal device in the first local area network and the first network element.

Specifically, when the first network element is an AMF network element, the AMF network element converts a connection state of a terminal device in the first local area network associated with the N2 interface into an idle state, and simultaneously informs an edge user plane function network element by means of the SMF network element to release an N3 tunnel of the terminal device newly converted into the idle state, at this time, the AMF network element cannot receive signaling of the idle state terminal device in the first local area network. If the connection between the core network and the first local area network has not been restored after a tracking area update (tracking area update, TAU) period time (typically 54 minutes), the session information of these terminal devices is released.

When the first network element is an SMF network element, the SMF network element is connected with the edge user plane function network element through an N4 interface, and when the first local area network is disconnected with the core network, the SMF network element deactivates the connection state of the terminal equipment served by the edge user plane function network element, and PDU session and tunnel resources are released.

Based on the embodiment of fig. 5, the keep-alive information is configured in advance for the AMF network element and the SMF network element in the core network, and the keep-alive function is started. Under the condition that no extra equipment is added, the AMF network element and the SMF network element can ensure the connection state of terminal equipment in the local area network to be kept in communication connection in the keep-alive information when facing to human or natural disasters. After the connection between the core network and the local area network on the keep-alive information is restored, the terminal equipment in the local area network does not need to initiate a registration process again and establish a PDU session, and therefore service interruption in the local area network is avoided. According to the embodiment of the application, the terminal equipment which is not exclusive to the mixed private network is not required to be added, and when the core network is disconnected from the local area network end only by enhancing the function of the 5GC key network element, the requirement of the service persistence stability of the private network with high-reliability disaster tolerance requirement is accurately met, so that the reliability of the private network service is improved, and meanwhile, the resource cost is not increased.

Referring to fig. 6, after the first network element resumes the connection with the first local area network, the method further comprises the following steps.

S601, a first network element acquires a second-class PDU session between a terminal device in a first local area network and the first network element.

The second type PDU session includes PDU session of terminal equipment in the first local area network maintained by the first network element between disconnection and connection recovery of the first network element and the first local area network.

As can be seen from step S502, when the keep-alive information includes the identifier of the first lan, the first network element maintains the connection state of the terminal device in the first lan, that is, does not delete the PDU session of the terminal device in the first lan. Between the disconnection and the restoration of the connection of the core network to the first local area network, the operator may delete any PDU session maintained by the first network element in the core network directly. As such, the number of PDU sessions maintained by the first network element before the core network is disconnected from the first lan may be different from the number of PDU sessions maintained by the first network element when the core network resumes connection with the first lan.

S602, the first network element acquires a first PDU session sent by an edge user plane function network element in the first local area network.

After the first network element is connected with the first local area network and is recovered, the first network element can acquire a first PDU session sent by an edge user plane function network element in the first local area network through an N4 interface.

S603, the first network element judges whether the same PDU session exists in the first-type PDU session and the second-type PDU session.

If the first type PDU session and the second type PDU session exist the same PDU session, executing S604; if there are different PDU sessions for the first type PDU session and the second type PDU session, S605 is performed.

S604, the first network element maintains the same PDU session.

Illustratively, if the first network element maintains the first PDU session, the second PDU session, and the third PDU session until the core network is disconnected from the first lan. When the first local area network is disconnected from the core network, the operator selects to release the third PDU session, and the first network element maintains the first PDU session and the second PDU session between the disconnection of the first local area network from the core network and the connection recovery. I.e. the second type of PDU session comprises a first PDU session and a second PDU session.

In this way, the first network element compares the first type PDU session sent by the edge user plane function network element in the first local area network with the second type PDU session maintained by the first network element, the first type PDU session comprises the second PDU session and the third PDU session, and the PDU session with the same first type PDU session and the second type PDU session is found to be the second PDU session. The first network element continues to keep the second PDU session, so that the original session can be used when the terminal equipment corresponding to the second PDU session resumes the connection with the first local area network without reestablishing the PDU session, and the continuity of the session is ensured.

S605, the first network element releases the different PDU session.

Illustratively, by comparing that the different PDU session of the first type PDU session and the second type PDU session is the first PDU session, the first network element releases the first PDU session.

Specifically, when the first network element is an SMF network element, the SMF network element releases the first PDU session, and deletes the tunnel resource and the context of the first PDU session.

Based on the embodiment of fig. 6, when the core network is restored to the first lan, the first network element and the edge user plane network element in the first lan maintain the same PDU session, so that the terminal device corresponding to the same PDU session does not need to reestablish the PDU session after the core network is restored to the first lan, and the different PDU sessions are deleted, so that tunnel resources occupied by the different PDU sessions can be released, and the utilization rate of network resources is improved.

After the connection between the core network and the first local area network is restored, the first network element can send the second-class PDU session to the edge user plane function network element in the first local area network through the N4 interface, which is beneficial to the edge user plane function network element in the first local area network to compare the first-class PDU session with the second-class PDU session, further, the same PDU session in the two-class PDU session is kept, different PDU sessions are released, and further, tunnel resources occupied by different PDU sessions can be released, and the utilization rate of network resources is improved. Illustratively, as shown in FIG. 7, the method further comprises: s606, the first network element sends the second PDU session to the edge user plane function network element in the first LAN. Thus, the edge user plane function network element in the first local area network is facilitated to receive the second type PDU session.

The disaster recovery method provided by the embodiment of the application configures keep-alive information in advance in the AMF network element and the SMF network element in the public network, and starts the keep-alive function of the AMF network element and the SMF network element in the public network and the edge user plane function network element in the private network. When the AMF network element is disconnected with the N2 interface of the wireless access network element in the private network, the AMF network element checks the context of the connected UE associated with the broken N2 interface, checks whether PDU session between the AMF network element and the private network DNN on the keep-alive information is established, if yes, the connection state of the UE is maintained, and if no, the connection state of the UE is deactivated. When the SMF network element is disconnected with the N4 interface of the edge data surface functional network element, the SMF network element checks the context of the connected UE associated with the N4 interface, checks whether a PDU session with a private network DNN on the keep-alive information is established, if so, the PDU session of the UE is maintained, and if not, the PDU session is released. Therefore, when the connection between the public network and the private network is restored, the UE corresponding to the PDU session is not required to be registered again and establish the PDU session, and the interruption of service data transmission is avoided. When the edge user plane function network element is disconnected with the N4 interface of the public network SMF network element and the N9 interface of the public network user plane function network element, the edge user plane function network element continuously maintains PDU session of terminal equipment in the private network, and service data can be continuously forwarded between the terminal equipment and the private network data network, namely keep-alive operation is ensured. Thereby ensuring the reliability and stability of service data transmission in the private network.

When the connection between the public network and the private network is restored, the SMF network element and the edge user plane function network element in the public network check the PDU conversation context information held on the two network elements together, check whether the same PDU conversation exists on the two network elements at the same time, if the same PDU conversation exists, the SMF network element keeps the same PDU conversation, the edge user plane function network element keeps the user plane connection of the terminal equipment corresponding to the same PDU conversation, and the data of the terminal equipment is ensured to be forwarded continuously. The two network elements delete different PDU sessions, release tunnel resources occupied by different PDU sessions, and improve the utilization rate of network resources.

According to the disaster recovery method, the requirements of service persistence stability of the private network with high reliability disaster recovery requirements can be met accurately by enhancing the functions of the 5GC key network element while the terminal equipment and other node modules which are not exclusive to the hybrid private network are not added, and the resource cost is not increased while the service reliability of the private network is improved.

The above description has been presented mainly in terms of interaction between the nodes. It will be appreciated that each node, e.g. the edge user plane functional network element and the first network element, in order to implement the above-mentioned functions, comprises corresponding hardware structures and/or software modules performing each function. Those of skill in the art will readily appreciate that the various illustrative algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is implemented as hardware or computer software driven hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

According to the method, the edge user plane function network element and the first network element can be divided into the function modules according to the method example, for example, each function module can be divided corresponding to each function, and two or more functions can be integrated into one processing module. The integrated modules may be implemented in hardware or in software functional modules. It should be noted that the division of the modules in this application is illustrative, and is merely a logic function division, and other division manners may be implemented in practice.

Fig. 8 shows a schematic composition diagram of a communication device according to an embodiment of the present application. As shown in fig. 8, the communication apparatus 80 includes a processing unit 801, a receiving unit 802, and a transmitting unit 803. Optionally, the communication device 80 may further comprise a storage unit 804. The communication means 80 may be a network device or a chip or a system on a chip in a network device.

A processing unit 801, configured to maintain a user plane connection of a terminal device in a local area network when an edge user plane function network element is disconnected from a core network; and is also used for forwarding data in the local area network according to the user plane connection of the terminal equipment.

The processing unit 801 is specifically configured to not release a protocol data unit PDU session of a terminal device in the local area network.

And a receiving unit 802, configured to obtain a first type PDU session of a terminal device in the local area network when the connection between the edge user plane function network element and the core network is restored. The first kind of PDU session includes PDU session of terminal equipment in local area network maintained by edge user plane function network element between disconnection and restoration of connection between the edge user plane function network element and core network.

Optionally, the receiving unit 802 is further configured to obtain a second type PDU session sent by the first network element in the core network.

Optionally, the processing unit 801 is further configured to determine whether the first type PDU session and the second type PDU session have the same PDU session.

Optionally, the processing unit 801 is specifically configured to maintain the same PDU session when the first type PDU session and the second type PDU session exist the same PDU session.

A sending unit 803, configured to send a first type PDU session to a first network element in the core network.

Fig. 9 shows a schematic diagram of the composition of a communication device according to an embodiment of the present application. As shown in fig. 9, the communication apparatus 90 includes a processing unit 901, a receiving unit 902, and a transmitting unit 903. Optionally, the communication device 90 may further comprise a storage unit 904.

And the processing unit 901 is configured to determine whether the keep-alive information includes an identifier of the first local area network when the first network element is disconnected from the first local area network.

Optionally, the processing unit 901 is further configured to maintain a connection state between the terminal device and the first network element in the first local area network when the keep-alive information includes an identifier of the first local area network.

Optionally, the processing unit 901 is further configured to release a connection state between the terminal device and the first network element in the first local area network when the keep-alive information does not include the identifier of the first local area network.

Optionally, the processing unit 901 is specifically configured not to delete a protocol data unit PDU session between the terminal device and the first network element in the first local area network.

Optionally, the first network element includes an access mobility management function AMF network element and a session management function SMF network element.

Optionally, the processing unit 901 is specifically configured to, when the first network element is an AMF network element, connect the first network element with a radio access network element in the first local area network through an N2 interface, and keep a terminal device in the first local area network connected to a control plane of the first network element.

Optionally, the processing unit 901 is specifically configured to, when the first network element is an SMF network element, connect the first network element with a radio access network element in the first local area network through an N2 interface, and keep a PDU session between a terminal device in the first local area network and the first network element.

Optionally, the keep-alive information is configured before the first network element disconnects from the first local area network.

Optionally, the receiving unit 902 is configured to obtain, when the connection between the first network element and the first local area network is restored, a second type PDU session between the terminal device in the first local area network and the first network element, where the second type PDU session includes a PDU session between the first network element and the first local area network that is maintained by the first network element and between the disconnection and the restoration of the connection between the first network element and the first local area network.

Optionally, the receiving unit 902 is further configured to obtain a first type PDU session sent by an edge user plane function network element in the first local area network.

Optionally, the processing unit 901 is further configured to determine whether the same PDU session exists in the first type PDU session and the second type PDU session.

Optionally, the processing unit 901 is specifically configured to maintain the same PDU session when the same PDU session exists in the first type PDU session and the second type PDU session.

Optionally, the sending unit 903 is configured to send the second type PDU session to an edge user plane function network element in the first local area network.

The units in fig. 8 and 9 may also be referred to as modules, for example, the processing units may be referred to as processing modules. In addition, in the embodiments shown in fig. 8 and 9, the names of the respective units may be other than those shown in the drawings, and for example, the transmitting unit may also be referred to as a communication unit.

Each of the units in fig. 8 and 9 may be stored in a computer readable storage medium if implemented in the form of software functional modules and sold or used as a separate product. Based on such understanding, the technical solution of the embodiments of the present application may be essentially or a part contributing to the prior art or all or part of the technical solution may be embodied in the form of a software product stored in a storage medium, including several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor (processor) to perform all or part of the steps of the methods described in the embodiments of the present application. The storage medium storing the computer software product includes: a U-disk, a removable hard disk, a read-only memory (ROM), a random access memory (random access memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

The embodiment of the application further provides a hardware structure schematic of the communication device, as shown in fig. 10, where the communication device 10 includes a processor 11, and optionally, a memory 12 and a communication interface 13 connected to the processor 11. The processor 11, the memory 12 and the communication interface 13 are connected by a bus 14.

The processor 11 may be a central processing unit (central processing unit, CPU), a general purpose processor network processor (network processor, NP), a digital signal processor (digital signal processing, DSP), a microprocessor, a microcontroller, a programmable logic device (programmable logic device, PLD), or any combination thereof. The processor may also be any other means for performing a processing function, such as a circuit, device, or software module. The processor 11 may also include a plurality of CPUs, and the processor 11 may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. A processor herein may refer to one or more devices, circuits, or processing cores for processing data (e.g., computer program instructions).

In this embodiment of the present application, the processor 11 may be configured to implement the function of the processing unit 801 in the communication apparatus 80, and illustratively, the processor 11 may be configured to maintain a user plane connection of a terminal device in the local area network when an edge user plane functional network element is disconnected from a core network, and may also be configured to forward data in the local area network according to the user plane connection of the terminal device. The processor 11 may also be configured to implement the function of the processing unit 901 in the communication apparatus 90, where the processor 11 may be configured to determine, when the first network element is disconnected from the first lan, whether the keep-alive information includes an identifier of the first lan, and may also be configured to maintain, when the keep-alive information includes an identifier of the first lan, a connection state between the terminal device in the first lan and the first network element.

The memory 12 may be a read-only memory (ROM) or other type of static storage device that may store static information and instructions, a random access memory (random access memory, RAM) or other type of dynamic storage device that may store information and instructions, or an electrically erasable programmable read-only memory (electrically erasable programmable read-only memory, EEPROM), a compact disc read-only memory (compact disc read-only memory) or other optical disk storage, optical disk storage (including compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer, as the embodiments of the present application are not limited in this regard. The memory 12 may be independent or may be integrated with the processor 11. Wherein the memory 12 may contain computer program code. The processor 11 is configured to execute computer program code stored in the memory 12, thereby implementing the methods provided by the embodiments of the present application. The communication interface 13 may be used to communicate with other devices or communication networks (e.g., ethernet, radio access network (radio access network, RAN), wireless local area network (wireless local area networks, WLAN), etc.). The communication interface 13 may be a module, a circuit, a transceiver, or any device capable of enabling communication.

Bus 14 may be a peripheral component interconnect standard (peripheral component interconnect, PCI) bus or an extended industry standard architecture (extended industry standard architecture, EISA) bus, among others. The bus 14 may be classified as an address bus, a data bus, a control bus, or the like. For ease of illustration, only one thick line is shown in fig. 10, but not only one bus or one type of bus.

Alternatively, the schematic structure shown in fig. 10 may be used to illustrate the structure of the edge user plane function network element involved in the foregoing embodiment. The processor 11 is configured to control and manage actions of the edge user plane function network element, for example: the processor 11 is configured to support the edge user plane function network element to perform steps S201-S202 in fig. 2. The processor 11 may communicate with other devices, e.g. with a first network element, via a communication interface 13. The memory 12 is configured to store program codes and data of the edge user plane function network element, for example, data packets of a PDU session of a terminal device in a local area network maintained by the edge user plane function network element.

Alternatively, the schematic structure shown in fig. 10 may be used to illustrate the structure of the first network element involved in the foregoing embodiment. The processor 11 is configured to control and manage actions of the first network element, for example: the processor 11 is configured to support the terminal device to perform steps S501-S503 in fig. 5. The processor 11 may communicate with other devices, e.g. with an edge user plane function network element, via a communication interface 13. The memory 12 is configured to store program codes and data of the first network element, for example, PDU sessions of the terminal device in the first local area network, and signaling sent by the terminal device in the first local area network through the base station to establish a connection with the first network element.

Embodiments of the present application also provide a computer-readable storage medium comprising computer-executable instructions that, when run on a computer, cause the computer to perform any of the methods described above.

Embodiments of the present application also provide a computer program product comprising computer-executable instructions which, when run on a computer, cause the computer to perform any of the methods described above.

The embodiment of the application also provides a chip, which comprises: a processor and an interface through which the processor is coupled to the memory, which when executed by the processor executes a computer program or computer-executable instructions in the memory, cause any of the methods provided by the embodiments described above to be performed.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using a software program, it may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer-executable instructions. When the computer-executable instructions are loaded and executed on a computer, the processes or functions described in accordance with embodiments of the present application are produced in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer-executable instructions may be stored in or transmitted from one computer-readable storage medium to another, for example, from one website, computer, server, or data center by wired (e.g., coaxial cable, fiber optic, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). Computer readable storage media can be any available media that can be accessed by a computer or data storage devices including one or more servers, data centers, etc. that can be integrated with the media. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a Solid State Disk (SSD)), or the like.

Although the present application has been described herein in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed application, from a review of the figures, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Although the present application has been described in connection with specific features and embodiments thereof, it will be apparent that various modifications and combinations can be made without departing from the spirit and scope of the application. Accordingly, the specification and drawings are merely exemplary illustrations of the present application as defined in the appended claims and are considered to cover any and all modifications, variations, combinations, or equivalents that fall within the scope of the present application. It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the spirit or scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims and the equivalents thereof, the present application is intended to cover such modifications and variations.

Claims

1. A disaster recovery method, wherein the method is performed by an edge user plane function network element, the edge user plane function network element being configured to provide a function of a user plane function network element of a core network in a local area network, the edge user plane function network element being connected to the user plane function network element in the core network, the method comprising:

if the connection between the edge user plane function network element and the core network is disconnected, the edge user plane function network element keeps the user plane connection of the terminal equipment in the local area network;

forwarding data in the local area network according to the user plane connection of the terminal equipment;

if the connection between the edge user plane function network element and the core network is restored, the edge user plane function network element acquires a first PDU session of terminal equipment in the local area network, wherein the first PDU session comprises a PDU session of the terminal equipment in the local area network maintained by the edge user plane function network element between the disconnection and the restoration of the connection between the edge user plane function network element and the core network;

the edge user plane function network element obtains a second type PDU session sent by a first network element in the core network,

the edge user plane function network element determines whether the first type PDU session and the second type PDU session have the same PDU session,

And if the first-type PDU session and the second-type PDU session exist the same PDU session, the edge user plane function network element keeps the same PDU session.

2. The method of claim 1, wherein the edge user plane function network element maintaining the user plane connection of the terminal device in the local area network comprises not releasing a protocol data unit, PDU, session of the terminal device in the local area network.

3. The method according to claim 1 or 2, characterized in that the method further comprises:

and the edge user plane function network element sends the first-type PDU session to a first network element in the core network.

4. A disaster recovery method, wherein the method is performed by a first network element, the first network element being configured to provide a function of establishing a connection with a network element in a first local area network for communication, the method comprising:

when the connection between the first network element and the first local area network is disconnected, the first network element judges whether keep-alive information contains the identification of the first local area network or not, wherein the keep-alive information is used for indicating the local area network to be kept in communication connection;

if the keep-alive information contains the identifier of the first local area network, the connection state of the terminal equipment in the first local area network and the first network element is maintained;

If the keep-alive information does not contain the identifier of the first local area network, releasing the connection state of the terminal equipment in the first local area network and the first network element;

when the connection between the first network element and the first local area network is restored, the first network element acquires a second-type PDU session between the terminal equipment in the first local area network and the first network element, wherein the second-type PDU session comprises a PDU session between the disconnection and the restoration of the connection between the first network element and the first local area network, and the PDU session of the terminal equipment in the first local area network is maintained by the first network element;

the first network element acquires a first PDU session sent by an edge user plane function network element in the first local area network;

the first network element judges whether the same PDU session exists in the first-type PDU session and the second-type PDU session;

and if the same PDU session exists in the first-type PDU session and the second-type PDU session, the first network element keeps the same PDU session.

5. The method of claim 4, wherein maintaining the connection state of the terminal device in the first local area network with the first network element comprises not deleting protocol data unit, PDU, sessions of the terminal device in the first local area network with the first network element.

6. The method of claim 4, wherein the first network element comprises an access mobility management function, AMF, network element and a session management function, SMF, network element.

7. The method of claim 6, wherein if the keep-alive information includes an identifier of the first lan, maintaining a connection state between a terminal device in the first lan and the first network element, including:

if the first network element is an AMF network element, the first network element is connected with a wireless access network element in the first local area network through an N2 interface, and the first network element keeps the connection between terminal equipment in the first local area network and a control surface of the first network element;

and if the first network element is an SMF network element, the first network element is connected with an edge user plane function network element in the first local area network through an N4 interface, and the first network element keeps PDU session between terminal equipment in the first local area network and the first network element.

8. The method of claim 7, wherein the keep-alive information is configured prior to disconnection of the first network element from the first local area network.

9. The method according to any one of claims 5-8, further comprising:

And the first network element sends a second-type PDU session to the edge user plane function network element in the first local area network.

10. A communication device, comprising:

the processing unit is used for keeping the user plane connection of the terminal equipment in the local area network when the edge user plane functional network element is disconnected with the core network;

the processing unit is further configured to forward data in the local area network according to the user plane connection of the terminal device;

a receiving unit, configured to obtain a first type PDU session of a terminal device in the local area network if the edge user plane functional network element is connected to and recovered from the core network, where the first type PDU session includes a PDU session of the terminal device in the local area network maintained by the edge user plane functional network element between disconnection and connection recovery of the edge user plane functional network element and the core network;

the receiving unit is further configured to obtain a second type PDU session sent by the first network element in the core network;

the processing unit is further configured to determine whether the first type PDU session and the second type PDU session have the same PDU session;

the processing unit is specifically configured to maintain the same PDU session when the first type PDU session and the second type PDU session exist the same PDU session.

11. A communication device, comprising:

the processing unit is used for judging whether the keep-alive information contains the identification of the first local area network when the first network element is disconnected with the first local area network;

the processing unit is further configured to maintain a connection state between a terminal device in the first local area network and the first network element when the keep-alive information includes an identifier of the first local area network;

the processing unit is further configured to release a connection state between the terminal device and the first network element in the first local area network when the keep-alive information does not include the identifier of the first local area network;

a receiving unit, configured to obtain a second type PDU session between a terminal device in the first local area network and the first network element when the connection between the first network element and the first local area network is restored, where the second type PDU session includes a PDU session between the first network element and the first local area network and between the connection disconnection and the connection restoration of the first network element and the first local area network, where the first network element maintains the terminal device in the first local area network;

the receiving unit is further configured to obtain a first type PDU session sent by an edge user plane function network element in the first local area network;

the processing unit is further configured to determine whether the same PDU session exists in the first type PDU session and the second type PDU session;

The processing unit is specifically configured to maintain the same PDU session when the same PDU session exists in the first type PDU session and the second type PDU session.

12. A computer readable storage medium comprising computer instructions which, when run on a computer, cause the computer to perform the method of any of claims 1-9.